Hydroxyapatite was found to be a very efficient heterogeneous catalyst for the preparation of chalcone derivatives via Claisen–Schmidt condensation using microwave irradiation. The impact of water on the catalyst reactivity was studied and was thought to act as co-catalyst due to the high activation observed in its presence. To investigate the origin of this activation, different organic solvents of similar or higher microwave absorbance as/to water were also tested, and it was confirmed that water is acting as co-catalyst when combined with hydroxyapatite, making the process highly efficient. The catalyst was easily recovered and efficiently re-used.

Graphical abstractHydroxyapatite was found to be a very efficient heterogeneous catalyst for the preparation of chalcone derivatives via Claisen–Shmidt condensation using microwave irradiation. The impact of water on the catalyst reactivity was studied and demonstrated to act as co-catalyst when combined with hydroxyapatite, making the process highly efficient. The catalyst was easily recovered and efficiently re-used.Figure optionsDownload full-size imageDownload high-quality image (44 K)Download as PowerPoint slide